Expandable mandrel for hollow piles



Nov. 30, 1965 G. BARcus ETAL 3,220,195

- EXPANDABLE MANDREL FOR HOLLOW PILES Filed July 1, 1963 2 Sheets-Sheet1 Lawrence G. Barcus QQW w w 6 William R. Barcus 7 36 IN VEN TORS Mm W72 I BY wfi zsm Nov. 30, 1965 BARCUS ETAL 3,220,195

EXPANDABLE MANDREL FOR HOLLOW FILES Filed July 1, 1963 2 Sheets-Sheet 2Lawrence 6. Barcus William R. Barcus IN VENTORS M40162. wqfim UnitedStates Patent 3,220,195 EXPANDABLE MANDREL FOR HOLLOW FILES Lawrence G.Barcus and William R. Barcus, both of 1430 State Ave., Kansas City,Kaus. Filed July 1, 1963, Ser. No. 292,052 6 Claims. '(Cl. 6153.72)

This invention relates to the driving of tubular piles or shafts intothe ground and more particularly to an expandable type of deviceinserted in such piles by means of which driving force is transmittedthereto in an axial direction. The device of the present inventiontherefore involves certain improvements over the expandable type of piledriving mandrel disclosed in prior copending application Serial No.799,278, filed March 13, 1959, now Patent No. 3,167,924, dated Feb. 2,1955.

A primary object of the present invention therefore, is to provide anexpandable type of pile driving mandrel which is simple in construction,assembly and reliable in operation.

A further object of the present invention is to provide an expandabletype of pile driving mandrel consisting of an assembly of twosemi-cylindrical elongated members one of which is axially displaceablewith respect to the other and held in assembled relation thereto so thatupon such axial displacement, the semi-cylindrical members are displacedapart into engagement with the walls of a tubular pile into which themandrel is inserted so that driving force may then be transmittedthrough the mandrel to the tubular pile member for driving thereof intothe ground.

In accordance with the foregoing objects, the expandable mandrel of thepresent invention features the provision of a plurality of axiallyspaced guide pins slidably extending between the active and passivesemi-cylindrical members which form the mandrel, the guide pins beingdisposed at an angle to the longitudinal axis of the mandrel so thatdriving force applied to the active member for axial displacementthereof, will force the members apart in a direction perpendicular tothe longitudinal axis for engagement with the hollow pile.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is a side sectional view taken through the expandable mandreldisposed within a hollow pile in a collapsed condition.

FIGURE 2 is a side sectional view of the expandable mandrel in anexpanded condition.

FIGURE 3 is a top plan view of the expandable mandrel.

FIGURE 4 is a transverse sectional view taken substantially through aplane indicated by a section line 44 in FIGURE 1.

FIGURE 5 is a perspective view illustrating various disassembled partsof the expandable mandrel.

FIGURE 6 is an enlarged partial sectional view of a portion of theexpandable mandrel.

' FIGURE 7 is a partial sectional view taken substantially through aplane indicated by section line 77 in FIGURE 6.

Referring now to the drawings in detail, it will be observed fromFIGURES 1 and 2, that the expandable mandrel generally referred to byreference numeral 10, is adapted to be inserted within a hollow ortubular pile 12 having an upper open end 14 through which the mandrel isinserted and a lower closed end 16. The mandrel is therefore adapted tobe inserted into the hollow pile and 32 of said members abut each other.

12 in its collapsed condition as shown in FIGURE 1 after which a drivingmechanism (not shown) applies force to the upper end of the mandrel as aresult of which the mandrel is expanded into engagement with theinternal surfaces of the cylindrical wall 18 of the hollow pile as shownin FIGURE 2. The continued application of force to the upper end of themandrel in its expanded condition will therefore drive the hollow pile12 into the ground 20.

The expandable mandrel 10 is made up of two elongated members one ofwhich is the passive member 22 adapted to be disposed in an axiallyfixed position within the hollow pile when inserted thereinto while theother elongated member is the active member 24 adapted to be axiallydisplaced from the position illustrated in FIG- URE 1 to the positionillustrated in FIGURE 2 as a result of which the mandrel is expandedinto engagement with the walls of the pile. Accordingly, the passive andactive members are provided with pile-engaging surfaces 26 and 28respectively substantially parallel to the internal surfaces of thehollow pile into which the mandrel is inserted. It will therefore beapparent, that in the illustrated embodiment, the surfaces 26 and 28will substan-' tially form a cylinder when the confronting flat faces 30Each of the elongated members 22 and 24 is also provided with lowertapered portions 34 and 36 so as to facilitate insertion of the mandrelinto the hollow pile. When inserted however, the elongated members willbe axially displaced with respect to each other so that the upperdriving end portion 38 of the active member 24 will be above the drivingend portion 40 of the passive member. The driving mechanism willtherefore initially displace the active member 24 before its drivingforce is transmitted through the expanded mandrel to the hollow pile. I

The passive and active members are held in assembled relation to eachother whether in the collapsed or expanded condition by means of aplurality of axially spaced guide pin elements 42 slidably mountedwithin both of the elongated members. In this manner, the elongatedmembers 22 and 24 are maintained in parallel and laterally fixedrelation to each other so that the driving force applied to the upperend portion of the mandrel will be effective to expand thesemi-cylindrical surfaces 26 and 28 of the mandrel into uniformlydistributed engagement with the internal surfaces of the hollow pile.Each of the guide pins 42 is therefore slidably mounted within axiallyalined bores 44 and 46 disposed respectively within the passive member22 and the active member 24. The bores 46 within the active member 24extend completely through the active member from the pile-engagingsurface 28 thereof to the confronting face 32. It will also be observed,that the bores 46 are disposed at an angle to the confronting faces orthe longitudinal axis of the mandrel so that the guide pin 42 slidablymounted therewithin, will cam the elongated members apart when drivingforce is applied to the upper driving end 38 of the member 24. In orderto hold the guide pin 42 assembled Within the axially alined bores, asemi-cylindrical stop disk element 48 is welded within the bore 46adjacent the end 54) thereof as more clearly seen in FIGURES 6 and 7.The bore 44 disposed within the passive member 22 in axial alinementwith the bore 46, extends from the confronting face 30 of the member 22but terminates Within the member spaced from the pile-engaging surface26 thereof. A vent passage 52 connects the end of the bore 44 with thepile-engaging surface so as to prevent pressure lock-up of the mandrelinits expanded condition when the ends of the guide pins 42 are spacedfrom the terminal ends of the bores 44 as illustrated in FIGURE 2. Itwill therefore be apparent,

that the guide pins 42 are of a length slightly smaller than the totallength of the alined bores 44 and 46. It will also be appreciated, thatthe number of guide pins and associated bores utilized will depend uponthe length of the mandrel and the loads to be sustained. It is also essential that the axis of the guide pins 42 intersect the longitudinalaxis of the mandrel at an angle so that the guide pins extend upwardlyfrom the pile-engaging surface 28 of the active member 24. A downwardlyapplied force to the driving end portion 38 of the active member willtherefore cam the members apart.

In order to collapse the mandrel from its expanded condition, a liftelement 54 is provided. A bevelled groove 56 is therefore formed inspaced adjacency to the driving end portion 38 of the active member sothat the lift element 54 may be inserted therein and held in the grooveby pins 58 which extend into the active member as more clearly seen inFIGURE 5. The lift element which is in the form of a semi-cylindricaldisk having an inner semicircular cut-out portion 60, may thereby belocated in non-interfering relation to the passive member 22 after whichthe lift element is welded in place. An upward displacing force maytherefore be applied to the active member 24 through the lift element 54in order to collapse the mandrel.

From the foregoing description, the construction, operation and utilityof the expandable mandrel will be apparent. It should therefore beappreciated, that the assembly of the present invention will provide aneffective method for transmitting driving force to a hollow pile andavoids the use of costly, complicated and fragile expanding devicesheretofore associated with expandable types of mandrels. Also, thearrangement of the present invention whereby the mandrel may beexpanded, involves substantially little weakening of the mandrel membersor sections necessary to accommodate the expanding guide pins that notonly effect expansion of the members but also maintain parallelismbetween the mandrel-engaging surfaces and the pile so as to obtaineffective engagement therewith.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. In combination with a tubular pile having a longitudinal axis, anexpandable mandrel adapted to drive said pile into the groundcomprising, an elongated passive member and an elongated active member,said members having confronting faces and pile engaging surfaces, saidpassive member being disposed in axially fixed position within thetubular pile and having a lower end portion axially engaging the pile,said active member being axially displaceable within the pile and havinga lower end portion and an upper driving end portion, and means mountedwithin both of said elongated members and extending between theconfronting faces thereof for maintaining said confronting faces inparallel and laterally fixed relation to each other when displaced inresponse to axial displacement of said active member by a driving forceat the driving end portion thereof, said last-mentioned means including,an elongated pin slidably mounted in axially aligned bores formed insaid elongated members, the bore in said active member extending at anangle to said longitudinal axis from the pile-engaging surface throughthe confronting face, a stop element fixed in the bore of the activemember adjacent the pile-engaging surface to limit movement of theelongated pin within said axially aligned bores, the bore in saidpassive member extending at an angle to the longitudinal axis from theconfronting face terminating within the passive member spaced from thepileengaging surface thereof, said passive member being formed with avent passage between the bore therein and the pile-engaging surfacethereof.

2. The combination of claim 1 wherein the lower end portions of saidelongated members are tapered for insertion thereof in the tubular pile,and including a lift element secured to the active member adjacent thedriving end portion thereof.

3. In combination with a tubular pile, an expandable mandrel adapted todrive said pile into the ground comprising, an elongated passive memberand an elongated active member, said members having confronting facesand pile-engaging surfaces, said passive member being disposed inaxially fixed position within the tubular pile having a lower endportion axially engaging the pile, said active member being axiallydisplaceable within the pile having a lower end portion axially spacedfrom the lower end portion of the passive member and an upper drivingend portion, and at least two axially spaced guide pins slidably mountedwithin both of the elongated members and extending between theconfronting faces thereof at an angle, whereby said elongated membersare maintained in parallel and laterally fixed relation to each otherwhen the active member is axially displaced by a driving force at thedriving end portion thereof to expand the pileengaging surfaces intoengagement with the pile as the axial spacing between the lower endportions of the elongated members is reduced.

4. The combination of claim 3 wherein said pileengaging surfaces of thepassive and active members form a continuous external periphery incross-section substantially parallel to the tubular pile incross-section.

5. In combination with a tubular pile having a longitudinal axis, anexpandable mandrel for driving said pile in a direction parallel to saidaxis comprising a pair of axially elongated members received within thepile in axially spaced relation to each other, each of said elongatedmembers having a pile engaging surface, a plurality of axially spacedguide elements, means mounting said guide elements within the elongatedmembers for relative slidable displacement at an angle to thelongitudinal axis in response to axial displacement of one of saidelongated members, confronting face means on said elongated membersengageable to limit said displacement of the guide elements in onedirection withdrawing said pile engaging surfaces from the pile andforce applying means connected to said one of the elongated members forsaid axial displacement thereof parallel to the longitudinal axis toengage the pile with said pile engaging surfaces and withdraw the samefrom engagement.

6. The combination of claim 5 wherein each of said elongated'members issubstantially solid in cross-section, said means slidably mounting theguide elements being formed by axially aligned bores extending throughthe elongated member along axes intersecting the confronting face meansat said angle to the longitudinal axis, the pile engaging surfaces andthe confronting face means defining the cross-sections of the elongatedmembers.

References Cited by the Examiner UNITED STATES PATENTS 589,026 8/1897Raymond 6l53.72 X 2,818,618 1/1958 Winship et al. 24272.l X 2,928,2523/1960 McKee 6l53.72

CHARLES E. OCONNELL, Primary Examiner.

JACOB SHAPIRO, Examiner.

3. IN COMBINATION WITH A TUBULAR PILE, AN EXPANDABLE MANDREL ADAPTED TODRIVE SAID PILE INTO THE GROUND COMPRISING, AN ELONGATED PASSIVE MEMBERAND AN ELONGATED ACTIVE MEMBER, SAID MEMBERS HAVING CONFRONTING FACESAND PILE-ENGAGING SURFACES, SAID PASSIVE MEMBER BEING DISPOSED INAXIALLY FIXED POSITION WITHIN THE TUBULAR PILE HAVING A LOWER ENDPORTION AXIALLY ENGAGING THE PILE, SAID ACTIVE MEMBER BEING AXIALLYDISPLACEABLE WITHIN THE PILE HAVING A LOWER END PORTION AXIALLY SPACEDFROM THE LOWER END PORTION OF THE PASSIVE MEMBER AND AN UPPER DRIVINGEND PORTION, AND AT LEAST TWO AXIALLY SPACED GUIDE PINS SLIDABLY MOUNTEDWITHIN BOTH OF THE ELONGATED MEMBERS AND EXTENDING BETWEEN THECONFRONTING FACES THEREOF AT